Nonvolatile memory devices are an important element of electronic systems due to their ability to maintain data absent a power supply. Some nonvolatile memory cells include phase change materials. Phase change materials include chalcogenide compounds that are capable of stably transitioning between physical states (e.g., amorphous, semi-amorphous, and crystalline states). Each physical state of the phase change material may exhibit a particular resistance that may be used to distinguish a logic value of the memory cell. Conventional memory cells including the phase change materials may also include a selector device, such as a switching diode, a threshold switching material, another isolation element, etc.
A semiconductor structure including an array of memory cells may include memory cells located at an intersection between conductive access lines, such as between a conductive word line and a conductive bit line. For example, three-dimensional (3D) cross-point memory devices may include memory cells arranged in an array and including rows of access lines and columns of access lines that may be arranged in a pattern of rows and columns. During operation of the semiconductor structure, data may be written to and read from the memory cells. A particular memory cell may be accessed through the conductive access lines in direct electrical communication with that particular memory cell.
Fabrication of conventional semiconductor structures including such memory cells often includes creating high aspect ratio openings in a stack of materials to form stack structures. Frequently, materials that are highly sensitive to downstream processing conditions are used as part of the stack structures. For example, chalcogenide materials of the phase change material may be damaged at temperatures used during conventional semiconductor fabrication processes or may react with etchant or deposition chemistries used during downstream processing. Elements of the chalcogenide materials may also diffuse out of the chalcogenide material during etching or material formation (e.g., deposition) act. In some situations, as a result of undesired interactions of the chalcogenide material with other materials in the stack, the chalcogenide material may undesirably have a different composition after fabrication of the semiconductor structure than an as-deposited chalcogenide material. Accordingly, patterning the stack structures and associated memory elements may result in undesirable effect such as damaging and contaminating sidewalls of the stack structures being patterned.